PBR Textures

The term “Physically Based Rendering” — or PBR — does, in itself, imply that the material definition used in PBR is based on real physics. Some have also interpreted this as meaning that other shading models are not based on real physics; which is wrong.

While real-time rendering shading models were not necessarily based on real physics, other ray tracers, such as V-Ray, have always been physically based. As such, PBR shading models became very popular for real-time rendering for two basic reasons: 

1. It is actually physically based.
2. It requires fewer variables — and therefore texture maps — to define a material.

There are two different modes of PBR, one of them is based on the Roughness and Metalic maps, the other is based on the Glossiness and Specular maps.
So when to see Sets of textures that have the Roughness or Metalic map is because it works with the first method and if the Set of textures contain the Specular or Glossiness map it is because it works with the second method.

V-Ray accepts both methods, but the default is Glossiness Specular.
These textures that are downloadable in Share Textures were created for this Glossiness Specular method.

So just apply the Diffuse on the Diffuse channel of VRayMtl, the Specular on the RGlossiness channel, the Normal on the Bump channel, but first you need to add the VRayNormalMap map and inside it apply the Normal texture, as is common with any Normal texture, in Displacement applies to the Displace channel, as shown in the first image attached.

However, the Displace of the material does not subdivide the Mesh, so you need to apply a mesh with enough polygons to reproduce Displacement details, I used a Plane with 100 x 100 Segments.
For more details on Displacement, it is better to apply the VRayDisplacementMod modifier and put the texture inside it, since it will subdivide the Mesh at the time of rendering and create finer details.

The AO is not usually used in rendering by Ray-Tracing, only in Games Engines or similar renderers like the Marmoset Toolbag.
However, you can use it to make compositions, as the AO map defines the most hidden parts of the Mesh in Black and the most accessible parts in White, so it is possible to apply it as a mask to compose two textures.

For example, if you apply the Composite map in the Slot Color and then add the texture of the Diffuse, you can create another Layer with another PBR texture, in my case I used earth, and apply the map of AO in the Mask of this Layer to define where it will or will not sand.
Since the AO map defines the protrusions of the Mesh, the sand texture will appear more in the parts where it would naturally accumulate between the stones, as shown in the third and fourth attached images.

About compositing in the Slate Material Editor or in the Compact Material Editor, both are the same, but it is more practical to use Slate in the composition of complex materials, and Compact is better at setting up simple materials.

Orjinal Portuguese: André Vieira